An eighth note.

Venous stenosis is the most common cause of arteriovenous fistula (AVF) failure in hemodialysis patients. For patients with AVF stenosis, the pressure over the antecedent part of the AVF stenotic lesion will increase if arterial inflow is sufficient. We report a chronic hemodialysis patient who received an angiographic examination for the juxta-anastomosis stenosis of his AVF. A unique feature of a collateral venous branch antecedent to the stenotic lesion was noted, resembling a musical sign as the "eighth note." After percutaneous transluminal angioplasty, the eighth note attenuated markedly at once. Of note, the eighth note sign is not seen frequently, and thus we postulate that the formation of an eighth note sign on the radiocephalic fistula should fulfill the following requirements, including a sufficient arterial inflow, an adjacent collateral branch close enough to the arteriovenous anastomosis, a severe juxta-anastomotic stenotic lesion, and an intact ulnar venous drainage system.

Preparation of unconventional dendrimers that contain rigid NH-triazine linkages and peripheral tert-butyl moieties for CO2 -selective adsorption.

Three unconventional dendrimers that contained rigid NH-triazine linkages and peripheral tert-butyl moieties were prepared by using a convergent approach and characterized by (1)H and (13)C NMR spectroscopy, mass spectrometry, and elemental analysis. Based on a thermogravimetric analysis study, these dendrimers were observed to display thermal stability at about 300 °C. The NH-triazine moiety, which possessed protonated and proton-free nitrogen sites (like the imidazole unit), displayed the capture of polarizable CO2 molecules through hydrogen-bond and/or dipole-quadrupole interactions. In addition, the adsorption of various amounts of CO2 and N2 at different pressures suggests that the dendritic pores, which arise from the stacking of the middle co-planar and rim protuberant dendrimers, Gn -N∼N-Gn (n=1-3), either swell or shrink at high pressure, thus indicating that these dendrimers may have a breathing ability.

Creation of Dual Thermally Activated Delayed-Fluorescence Exciplexes in a Bulk Emitting Layer and Its Interface with an Electron Transport Layer for Promoting the Performance of Thermally Activated Delayed-Fluorescence Organic Light-Emitting Diodes Fabricated by a Solution Process.

An exciplex, which is composed of electron donor and acceptor molecules and formed by intermolecular charge transfer, is an excited-state species that is able to emit light or transfer its energy to a lower-energy emitter. In reported exciplex-based organic light-emitting diodes (OLEDs), their working mechanism is to generate exciplexes either in the bulk emitting layer (bulk exciplex) or at its interface with an electron transport layer (interface exciplex); both types give promising device performance. Here, we propose a novel strategy of creating both types of exciplexes simultaneously (dual exciplexes) for the generation of more exciplexes for better device performance as indicated in the improved photoluminescence quantum yield (PLQY). Impressively, the dual exciplex-based device with blue thermally activated delayed fluorescence (TADF) emitter 9,9-dimethyl-9,10-dihydroacridine-2,4,6-triphenyl-1,3,5-triazine (DMAC-TRZ) exhibits a record-high maximum external quantum efficiency (EQEmax) of 26.7% among the solution-processed TADF blue OLEDs. By further doping with the red-emitting phosphor emitter into the EML, the white device also gives a record-high EQEmax of 24.1% among the solution-processed TADF-phosphor hybrid white OLEDs (T-P WOLEDs) with the Commission Internationale de L'Eclairage (CIE) coordinates of (0.34, 0.42), color rendering index of 70, and correlated color temperature of 5198 K. Furthermore, both blue and white devices show an ultralow efficiency roll-off with external quantum efficiencies at a practical brightness value of 1000 cd m-2 (EQE1000) of 25.1 and 23.9%, respectively. This is the first report of employing a dual exciplex-based OLED with excellent device performance.

Synthesis, characterization and structural transformation of a discrete tetragonal metalloprism.

A novel M(2)L(4) tetragonal metalloprism, [(NO(3)(-))⊂{Cu(2)(µ-Hdpma)(4)}(NO(3))(2)](NO(3))(5) (1), was prepared from the self-assembly reaction of Cu(NO(3))(2)·3H(2)O and flexible clip-like organic ligand di(3-pyridylmethyl)amine (dpma) under acidic conditions. The cationic prismatic hollow structure of 1 hosts one nitrate anion via both metal-ligand dative bonds and electrostatic interactions. Metalloprism 1 can dissolve in water and its prismatic structure remains intact as supported by ESI-MS data. When metalloprism 1 was treated with sodium thiocyanate and sodium azide in aqueous solutions, two polymeric coordination architectures, [Cu(µ-Hdpma)(2)(NCS)(2)](NO(3))(2) (2) and [Cu(µ-dpma)(2)(µ-1,1-N(3))(µ-1,3-N(3))] (3), formed at room temperature, respectively. Polymer 2 has a two-dimensional sheet structure showing a simple rhombic 4(4)-sql topology in network connectivity, whereas polymer 3 gives a three-dimensional uninodal pcu net. The conformation of the flexible ditopic ligand is varied from a trans-trans-syn conformer in 1 to a trans-trans-anti conformer in 2 and to a trans-gauche-anti conformer in 3. The observations imply the occurrence of structural transformation from a discrete metalloprism into polymeric coordination architectures via a decoordination/rearrangement process. Magnetic studies of metalloprism 1 suggest that the two Cu(II) centers are weakly antiferromagnetically coupled. The spins communicate via the nitrate template while the Cu···O(nitrate) interactions are weak. For polymer 3, a ferromagnetically coupled system (J(2) = +17.6 cm(-1)) is operative between two Cu(II) centers bridged by end-on azidos and an antiferromagnetic coupling (J(1) = -7.7 cm(-1)) between two Cu(II) centers with end-to-end azidos. In contrast to relatively large coupling values of the reported examples, the weak ferromagnetic interaction results from insufficient spin delocalization between two Cu(II) centers.